Preparation of organic pieces of optical quality and especially organic lenses

Abstract

The main aim of the present invention is a method of preparing photochromic or non-photochromic organic pieces of optical quality and especially organic lenses, by radical polymerisation of a mixture of radically polymerisable monomers, characterised in that it comprises: a) adjusting, by pre-polymerisation, the viscosity of said mixture, to a value between 0.4 and 2 Pa.s; b) pouring said pre-polymerised mixture into a mould; c) photogelifying, in said mould, said pre-polymerised mixture until its gel point; d) completing the polymerisation of said pre-polymerised and gelified mixture in said mould, by heat treatment; adding effective amounts of at least one thermal catalyst and of at least one photoinitiator intervening in said mixture of monomers for the implementation of said pre-polymerisation, photogelification and polymerisation; said photoinitiator(s) intervening in an amount less than or equal to 0.009 parts by weight per 100 parts by weight of said mixture of monomers.

What is claimed is:  
     
       1. A method of preparing photochromic or non-photochromic organic articles of optical quality by radical polymerisation of a mixture of radically polymerisable monomers, wherein said method comprises: 
       a) adjusting, by pre-polymerisation, the viscosity of said mixture to a value between 0.4 and 2 Pa.s;  
       b) pouring said pre-polymerised mixture into a mould;  
       c) photogelifying, in said mould, said pre-polymerised mixture until its gel point;  
       d) completing the polymerisation of said pre-polymerised and gelified mixture in said mould by heat treatment;  
       wherein the method further comprises adding an effective amount of at least one thermal catalyst and of at least one photoinitiator in said mixture of monomers for the implementation of said pre-polymerisation, photogelification, and polymerisation; wherein said photoinitiator(s) are present in an amount less than or equal to 0.009 parts by weight per 100 parts by weight of said mixture of monomers;  
       and wherein said mixture of monomers comprises one or more difunctional monomers having formula (A) or formula (A′) and one or more difunctional monomers having formula (B), (B′), or (B″), wherein formula (A) is                    
       in which:  
       R 1 , R′ 1 , R, and R′, identical or different, are independently a hydrogen or a methyl group;  
       m and n are, independently, integers between 0 and 4, inclusive;  
       X and X′, identical or different, are a halogen; and  
       p and g are, independently, integers between 0 and 4, inclusive;  
       wherein formula (A′) is                    
       in which:  
       R 1 , and R′ 1 , identical or different, are independently a hydrogen or a methyl group; and  
       R is a straight or branched alkyl radical having 2 to 8 carbon atoms, a cycloalkyl radical having 3 to 6 carbon atoms, or an ether radical of formula (R′—O—R″) in which R′ and R″, identical or different, are independently a straight or branched alkyl radical having 2 to 4 carbon atoms;  
       wherein formula (B) is                    
       in which:  
       R 1 , R′ 1 , R 2 , and R′ 2 , identical or different, are independently hydrogen or a straight or branched alkyl radical;  
       R 3  and R 4 , different, are independently one hydrogen and the other an alkenyl radical having 2 to 6 carbon atoms;  
       R′ 3  and R′ 4 , different, are independently one hydrogen and the other an alkenyl radical having 2 to 6 carbon atoms;  
       Z represents a carbamate function (—NH—CO—O—), a thiocarbamate function (—NH—CO—S—), or a urea function (—NH—CO—NH—);  
       Z′, independent from Z, represents a carbamate function (—O—CO—NH—), a thiocarbamate function (—S—CO—NH—), or a urea function (—NH—CO—NH—);  
       R′ represents a straight or branched alkyl radical having 2 to 4 carbon atoms;  
       R, identical or different when n≧2, is a straight or branched alkyl radical having 2 to 4 carbon atoms;  
       Y, identical or different when n≧2, is oxygen or sulphur; and  
       n is an integer defined such that the total number of carbon atoms contained in the long chain situated between the two moieties Z and Z′ is at least equal to 18;  
       wherein formula (B′) is                    
       in which:  
       R 1 , R 2 , R 3 , R 4 , R′ 1 , R′ 2 , R′ 3 , R′ 4 , R, and Y are as defined above with reference to formula (B); and  
       n is an integer defined such that the total number of carbon atoms contained in the long chain of moiety (R—Y) n  is at least equal to 22; and  
       wherein formula (B″) is                    
       in which:  
       R 1 , R 2 , R 3 , R 4 , R′ 1 , R′ 2 , R′ 3 , R′ 4 , R, R′, and Y are as defined above with reference to formula (B);  
       Z′ is a carbamate function (—O—CO—NH—), or Z′ is a thiocarbamate function (—S—CO—NH—); and  
       n is an integer defined such that the total number of carbon atoms contained in the long chain of moiety (R—Y) n R′ is at least equal to 22.  
     
     
       2. The method according to claim  1 , wherein said pre-polymerisation is a thermal pre-polymerisation or a photochemical pre-polymerisation or a combination thereof. 
     
     
       3. The method according to claim  1 , wherein said pre-polymerisation is a thermal pre-polymerisation; wherein the thermal pre-polymerisation is carried out on the mixture of monomers containing the effective amounts of thermal catalyst(s) and photoinitiator(s); or wherein the thermal pre-polymerisation is carried out on the mixture of monomers containing only the effective amount of thermal catalyst(s), the effective amount of photoinitiator(s) being then added to said mixture of monomers upon completion of the thermal pre-polymerisation and before the pre-polymerised mixture is poured into the mould. 
     
     
       4. The method according to claim  1 , wherein said pre-polymerisation is a photochemical pre-polymerisation; wherein said photochemical pre-polymerisation is carried out on the mixture of monomers containing an amount of photoinitiator(s) effective to carry out said photochemical pre-polymerisation; and wherein the effective amount of thermal catalyst(s) is added to said mixture of monomers before its photochemical pre-polymerisation or upon completion thereof. 
     
     
       5. The method according to claim  4 , wherein the amount of photoinitiator present during said photochemical pre-polymerisation is from 40% to 60% of said effective amount expressed by weight; and wherein the remainder of photoinitiator(s) is added to said mixture of monomers upon completion of the photochemical pre-polymerisation and before it is poured into the mould. 
     
     
       6. The method according to claim  1 , wherein said photogelification is carried out using radiation which is predominantly visible radiation and which is substantially free from ultraviolet radiation. 
     
     
       7. The method according to claim  6 , wherein said pre-polymerisation is a photochemical pre-polymerisation and wherein said photochemical pre-polymerisation is carried out using radiation which is predominantly visible radiation and which is substantially free from ultraviolet radiation. 
     
     
       8. The method according to claim  1 , wherein said mixture of monomers comprises acrylic and/or methacrylic and/or alkenyl monomers. 
     
     
       9. The method according to claim  1 , wherein said mixture of monomers comprises at least one monomer having formula (B) in which: 
       Z and Z′ are urea functions (—NH—CO—NH—);  
       R 1 , R′ 1 , R 2 , and R′ 2  are identical and represent a methyl group;  
       R 3  and R′ 3 , identical, represent an isopropenyl group;  
       R 4  and R′ 4 , identical, are hydrogen;  
       R′ represents an ethylene or propylene group; and  
       n is an integer equal to 13 or 19 which defines a total umber of carbon atoms, between Z and Z′, equal to 28 or 40 when (R—Y) n  is a polyoxyethylene chain; or n is an integer equal to 10 or 14 which defines a total number of carbon atoms, between Z and Z′, equal to 33 or 45 when (R—Y) n  is a polyoxy propylene chain; or n is an integer between the lower limit values (n is between 10 and 13 (inclusive)) and upper limit values (n is between 14 and 19 (inclusive)), when (R—Y) n  is a polyoxyethylene/polyoxypropylene mixed chain.  
     
     
       10. The method according to claim  1 , wherein said mixture of monomers further comprises: 
       at least one aromatic monovinylic monomer of formula (C):                    
       in which R 1 =H or CH 3 ; and/or 
       at least one aromatic divinylic monomer of formula (D):                    
       in which R 1 =H or CH 3 ; and/or 
       at least one (meth)acrylic monomer of formula (E):  
       
         
           CH 2 ═C (R)—COOR′ 
         
       
       in which R=H or CH 3  and R′ is a straight or branched alkyl radical having 4 to 16 carbon atoms, an optionally substituted benzyl or phenoxyethyl radical, or a polyethoxy group of formula —(CH 2 —CH 2 —O) n R″ in which n is an integer between 1 and 10 and R″=CH 3  or C 2 H 5 ; and/or 
       diallylphthalate.  
     
     
       11. The method according to claim  10 , wherein said at least one monovinylic monomer is styrene, wherein said at least one divinylic monomer is divinylbenzene, and wherein said at least one (meth)acrylic monomer is 2-ethylhexylmethacrylate. 
     
     
       12. The method according to claim  1 , wherein said mixture of monomers comprises at least one acrylic monomer having at least three acrylate functional groups. 
     
     
       13. The method according to claim  12 , wherein said at least one acrylic monomer having at least three acrylate functional groups is selected from the group consisting of pentaerythritol triacrylate, pentaerythritol tetraacrylate, propoxylated glycerol triacrylate, trimethylolpropane triacrylate, polyurethane triacrylate, and dipentaerythritol hexaacrylate. 
     
     
       14. The method according to claim  1 . wherein said mixture of monomers comprises an amount of at least one photochromic colorant effective to give photochromic properties to the organic pieces. 
     
     
       15. The method according to claim  1 , wherein said at least one thermal catalyst is a diazo compound. 
     
     
       16. The method according to claim  1 , wherein said at least one photoinitiator is a diacylphosphine oxide. 
     
     
       17. The method according to claim  1 , wherein the photochromic or non-photochromic organic article have a thickness between 0.2 and 20 mm. 
     
     
       18. The method according to claim  1 , wherein said photochromic or non-photochromic organic articles are photochromic or non-photochromic organic lenses. 
     
     
       19. Organic articles of optical quality prepared by the method according to claim  1 . 
     
     
       20. Organic articles of optical quality prepared by the method according to claim  12 . 
     
     
       21. Lenses prepared by the method according to claim  1 . 
     
     
       22. Lenses prepared by the method according to claim  12 . 
     
     
       23. Mixtures of radically polymerisable monomers, optionally comprising an effective amount of at least one photochromic colorant, wherein said mixtures comprise: 
       at least one difunctional monomer having formulae (A) or formula (A′) as defined in claim  1 ;  
       at least one difunctional monomer having formula (B), formula (B′), or formula (B″) as defined in claim  1 ; and  
       at least one acrylic monomer having at least three acrylate functional groups.  
     
     
       24. Mixtures of radically polymerisable monomer according to claim  23 , wherein said at least one acrylic monomer having at least three acrylate functional groups is selected from the group consisting of pentaerythritol triacrylate, pentaerythritol tetraacrylate, propoxylated glycerol triacrylate, trimethylolpropane triacrylate, polyurethane triacrylate, and dipentaerythritol hexaacrylate. 
     
     
       25. Mixtures of radically polymerisable monomers according to claim  23 , wherein said mixtures comprise: 
       at least one difunctional monomer having formula (A), as defined in claim  1 ;  
       at least one difunctional monomer having formula (B), as defined in claim  1 ;  
       at least one acrylic monomer having at least three acrylate functional groups;  
       at least one aromatic divinylic monomer of formula (D):                    
       in which R 1 =H or CH 3 ; and 
       at least one (meth)acrylic monomer of formula (E):  
       
         
           CH 2 =C(R)—COOR′ 
         
       
       in which R=H or CH 3  and R′ is a straight or branched alkyl radical having 4 to 16 carbon atoms, an optionally substituted benzyl or phenoxyethyl radical, or a polyethoxy group of formula —(CH 2 —CH 2 —O) n R″ in which n is an integer between 1 and 10 and R″=CH 3  or C 2 H 5 . 
     
     
       26. Mixtures of radically polymerisable monomer according to claim  25 , wherein said at least one acrylic monomer having at least three acrylate functional groups is selected from the group consisting of pentaerythritol triacrylate, pentaerythritol tetraacrylate, propoxylated glycerol triacrylate, trimethylolpropane triacrylate, polyurethane triacrylate, and dipentaerythritol hexaacrylate and wherein said at least one (meth)acrylic monomer is 2-ethylhexylmethacrylate.